Angular momentum evolution in an ﹩8\;{{\rm{M}}}_{\odot }+6\;{{\rm{M}}}_{\odot }﹩ binary with an initial orbital period of 1.5 days. Left panels show the evolution before the onset of RLOF, while right panels display evolution from the beginning of RLOF until contact, when both components fill their Roche lobe. The fractional error in the total angular momentum is plotted in the bottom panel and is of order machine-precision.